Liquid crystal displays (LCDs) are commonly used in various electronics, such as cell phones, laptops, electronic tablets, televisions, and computer monitors. Increased demand for larger, high-resolution flat panel displays drives the need for large high-quality glass substrates for use in the display. For example, glass substrates may be used as light guide plates in LCDs, to which a light source may be coupled. The thinness and/or screen size of an LCD device may be affected by the size and/or properties of the light-emitting and/or light-incident surfaces of the light guide.
The light-incident surface area of a glass substrate can be affected by the method by which the glass is cut. For instance, glass can be cut by a mechanical scoring technique to provide perforated dashes along which the glass can be broken a relatively straight line; however, this method may cause significant damage to the edge of the glass. To improve reliability and reduce chipping, the edges of the glass can be finished, often by introduction of a chamfer, which may eliminate all or a part of the damaged portion of the glass. While this technique may improve glass reliability, it may have adverse effects from an optical standpoint, as the chamfer can reduce the surface area at the edge of the light guide that is available to couple the light from the LED into the light guide. It would therefore be advantageous to reduce chamfering of the light-incident edge, as this may allow for a thinner light guide and thus a thinner overall LCD device.
The light-emitting surface area of a glass substrate can be affected by the presence of “hot spots” at the light-incident edge. Strips of LEDs, which can be optically coupled with the light guide plate, may comprise a plurality of individual LEDs, each separated by a gap. As a result of the gaps between each LED, the light emitted by the LEDs must propagate a significant distance down the light guide plate until homogeneous light is produced. The area on the light guide plate which does not receive homogeneous light is known as a hot spot zone. Hot spot zones are typically not usable for display and may be covered by a bezel or other structure around the perimeter of the display, which can limit the amount of the screen available to display an image. It would thus be advantageous to reduce the size of the hot spot zone, as this may allow for the production of LCDs with larger displays and thinner bezels.
Accordingly, it would be advantageous to provide light guide plates for display devices which address the aforementioned drawbacks, e.g., glass light guide plates with improved optical properties at the light-incident edges and reduced hot spot zones.